我尝试运行该程序，但它运行不正常。问题在于功能，但我不确切知道在哪里。我首先声明了函数，然后我尝试在main中调用它们。但是，我不确定是这样的。我认为问题在于函数定义？但我不知道还有什么可做的。如果有人能看到它并向我指出那将是伟大的。
#include <stdio.h>
#include <math.h>
float computeMonthlyPayment(float p, float YearRate, float YearTerm);
float computeMonthlyInterest(float p, float YearRate);
void printLoanInfo(float p, float MonthlyPayment, float YearRate, float r, float YearTerm, float n);
void printTable(float MonthlyPayment, float p, float YearRate,float YearTerm);
int main()
{
float n, p, r, MonthlyPayment, YearRate, YearTerm;
printf("Enter the loan amount: ");
scanf("%f", &p);
if (p <= 0.0)
printf("\nERROR: Invalid rate; must be greater than 0\n");
while (p <= 0.0)
{
printf("\nEnter the loan amount: ");
scanf("%f", &p);
}
printf("\nEnter annual interest rate: ");
scanf("%f", &YearRate);
if (YearRate <= 0.0 || YearRate > 30.0)
printf("\nERROR: Invalid rate; must be > 0.0 amd <= 30.0.\n");
while (YearRate <= 0.0 || YearRate > 30.0)
{
printf("\nEnter annual interest rate: ");
scanf("%f", &YearRate);
}
printf("\nEnter the term of the loan (in years): ");
scanf("%f", &YearTerm);
if (YearTerm <= 0.0)
printf("\nERROR: Invalid rate; must be greater than 0\n");
while (YearTerm <= 0.0)
{
printf("\nEnter the term of the loan (in years): ");
scanf("%f", &YearTerm);
}
float computeMonthlyInterest(float p, float YearRate);
float computeMonthlyPayment(float p, float YearRate, float YearTerm);
void printLoanInfo(float p, float MonthlyPayment, float YearRate, float r, float YearTerm, float n);
return 0;
}
float computeMonthlyPayment(float p, float YearRate, float YearTerm)
{
float r = YearRate/12;
float n = YearTerm*12;
float MonthlyPayment = 0;
MonthlyPayment = (r*p)/1-((1+r)/n);
return MonthlyPayment;
}
float computeMonthlyInterest(float p, float YearRate)
{
float r = 0;
r = ((YearRate)/12)/12;
return r;
}
void printLoanInfo(float p, float MonthlyPayment, float YearRate, float r, float YearTerm, float n)
{
printf("LOAN INFORMATION\n");
printf("-----------------------\n");
printf("Initial loan amount: %.2f\n", p);
printf("Annual interest rate: %.3f\n", YearRate);
printf("Monthly interest rate: %.3f\n", r);
printf("Term of loan (years): %f\n", YearTerm);
printf("Term of loan (months): %f\n", n);
printf("Monthly payment amount: %.2f\n", MonthlyPayment);
}
答案 0 :(得分：0)
在main()中查看第48..50行。
int main()
{
// ...
float computeMonthlyInterest(float p, float YearRate);
float computeMonthlyPayment(float p, float YearRate, float YearTerm);
void printLoanInfo(float p, float MonthlyPayment, float YearRate, float r, float YearTerm, float n);
// ...
}
这些是函数的原型，而不是你实际调用它们的方式。您应该按照调用printf()或scanf()的方式调用它们，方法是将相应的参数传递给它们。就目前而言，你只是重新声明main()中的函数，而不是实际调用它们。尝试这样的事情：
int main()
{
// ...
r = computeMonthlyInterest(p, YearRate); // r should be labeled better.
MonthlyPayment = computeMonthlyPayment(p, YearRate, YearTerm);
printLoanInfo(p, MonthlyPayment, YearRate, r, YearTerm, n);
// ...
}
但仍然没有100％修复，因为n未初始化。虽然printLoanInfo()说明了它的用途（这也是我确定r的方式），但您忘记在main()中设置它。所以..
int main()
{
// ...
r = computeMonthlyInterest(p, YearRate);
n = YearTerm * 12; // You did this in computeMonthlyPayment(), but not here.
MonthlyPayment = computeMonthlyPayment(p, YearRate, YearTerm);
printLoanInfo(p, MonthlyPayment, YearRate, r, YearTerm, n);
// ...
}
因此，考虑到这些变化，您的main()应该看起来像这样：
int main()
{
float n, p, r, MonthlyPayment, YearRate, YearTerm;
printf("Enter the loan amount: ");
scanf("%f", &p);
if (p <= 0.0)
printf("\nERROR: Invalid rate; must be greater than 0\n");
while (p <= 0.0)
{
printf("\nEnter the loan amount: ");
scanf("%f", &p);
}
printf("\nEnter annual interest rate: ");
scanf("%f", &YearRate);
if (YearRate <= 0.0 || YearRate > 30.0)
printf("\nERROR: Invalid rate; must be > 0.0 amd <= 30.0.\n");
while (YearRate <= 0.0 || YearRate > 30.0)
{
printf("\nEnter annual interest rate: ");
scanf("%f", &YearRate);
}
printf("\nEnter the term of the loan (in years): ");
scanf("%f", &YearTerm);
if (YearTerm <= 0.0)
printf("\nERROR: Invalid rate; must be greater than 0\n");
while (YearTerm <= 0.0)
{
printf("\nEnter the term of the loan (in years): ");
scanf("%f", &YearTerm);
}
// Remove these lines:
// float computeMonthlyInterest(float p, float YearRate);
// float computeMonthlyPayment(float p, float YearRate, float YearTerm);
// void printLoanInfo(float p, float MonthlyPayment, float YearRate, float r, float YearTerm, float n);
// Add these lines:
r = computeMonthlyInterest(p, YearRate);
n = YearTerm * 12;
MonthlyPayment = computeMonthlyPayment(p, YearRate, YearTerm);
printLoanInfo(p, MonthlyPayment, YearRate, r, YearTerm, n);
return 0;
}
答案 1 :(得分：0)
问题不在于功能定义。事实是，在main()中，您可以复制并粘贴这些行。
float computeMonthlyInterest(float p, float YearRate);
float computeMonthlyPayment(float p, float YearRate, float YearTerm);
void printLoanInfo(float p, float MonthlyPayment, float YearRate, float r, float YearTerm, float n);
这些函数声明通知编译器如何调用函数，但实际上并不调用它们。
如果您打算实际调用它们，则需要执行类似
的操作variable1 = computeMonthlyInterest(p, YearRate);
variable2 = computeMonthlyPayment(p, YearRate, YearTerm);
printLoanInfo(p, MonthlyPayment, YearRate, r, YearTerm, n);
本质上，这会从函数参数中删除类型规范并传递实际值。 variable1和variable2是在这些语句保存返回值之前需要定义的变量（可能具有更有意义的名称）。据推测，您还需要在main()中编写更多代码以使用这些变量。
答案 2 :(得分：0)
请记住其他答案所说的有关正确调用您的功能的内容。下面的代码应该有效。我不得不重新计算你的computeMonthlyPayment，因为它计算错误。
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