Question

当我在数组中插入字符值时，我的程序退出了。如果我插入字符值，我想继续我的循环没有退出程序并采取下一个整数值。我的代码中有什么不对。

我的代码：

#include<stdio.h>
#include<ctype.h>

int main()
{
    int row1, col1, row2, col2, i, j, k, sum = 0;
    int first[10][10], second[10][10], multiply[10][10];
    clrscr();
    printf("Enter the no of rows and columns of first matrix\n");
    scanf("%d%d",&row1,&col1);
    printf("Enter the Element of first matrix");
    for(i=0;i<row1;i++){
        for(j=0;j<col1;j++){
            printf("\nEnter %d element %d row",j+1,i+1);
            scanf("%d",&first[i][j]);
            check = first[i][j];
            printf("%d",check);
            if(check>0 || check<0)
            {
                printf("this is digit \n");
            }
            else
            {
                printf("this is not digit\n");
                printf("\nEnter %d element %d row",j+1,i+1);
                scanf("%d",&first[i][j]);
            }
        }
    }
    printf("Enter the no of rows and columns of second matrix\n");
    scanf("%d%d",&row2,&col2);

    if(col1 == row2){
        printf("Enter the Element of second matrix");
        for(i=0;i<row2;i++){
            for(j=0;j<col2;j++){
                printf("\nEnter %d element %d row",j+1,i+1);
                scanf("%d",&second[i][j]);
            }
        }

        for(i=0;i<row1;i++){
            for(j=0;j<col2;j++){
                for(k=0;k<row2;k++){
                    multiply[i][j]=sum;
                    sum=0;
                }
            }
        }
        printf("Multiplication of matrices=\n");
        for(i=0;i<row1;i++){
            for(j=0;j<col2;j++){
                multiply[i][j]=0;
                for(k=0;k<row1;k++){
                    multiply[i][j] += first[i][k] * second[k][j];
                }
                printf("%d\t",multiply[i][j]);
            }
            printf("\n");
        }
    }
    else{
        printf("You are incorrect. According to the requirement of matrix multiplication, the number of column of first matrix should equal to the number of rows of second matrix.");
    }
    getch();
    return 0;
}

感谢你

Answer 1

scanf返回已成功读取的条目数。当您尝试读取数字但提供的是非数字值时，scanf将返回零。在scanf返回1之前，您需要反复提示用户输入。以下是修改代码的一种方法：

for(;;) {
    printf("\nEnter %d element %d row",j+1,i+1);
    if (scanf("%d",&first[i][j]) == 1) break;
    // Read and ignore the invalid input. 's' means "string", '*' means "ignore".
    scanf("%*s");
    printf("\nThe data you entered was incorrect.");
}

Answer 2

执行时

scanf("%d",&first[i][j])

这意味着您的scanf只接受整数。如果输入字母字符，则scanf将不读取任何内容，然后返回0作为first[i][j]

的值

下一个scanf("%d");将无法获取您的输入（即使它们是数字），因为stdin尚未从字母字符中清除。

替换此

for(i=0;i<row1;i++){
        for(j=0;j<col1;j++){
            printf("\nEnter %d element %d row",j+1,i+1);
            scanf("%d",&first[i][j]);

通过

for(i=0;i<row1;i++){
        for(j=0;j<col1;j++){
            printf("\nEnter %d element %d row",j+1,i+1);
            while (scanf("%d",&first[i][j]))<=0) {
                printf("this is not digit\n");
                printf("\nEnter %d element %d row",j+1,i+1);
                scanf("%*[^\n]"); // this clean your input buffer in case yhe input is not integer
            }

并删除此块：

            check = first[i][j];
            printf("%d",check);
            if(check>0 || check<0)
            {
                printf("this is digit \n");
            }
            else
            {
                printf("this is not digit\n");
                printf("\nEnter %d element %d row",j+1,i+1);
                scanf("%d",&first[i][j]);
            }

如何验证c中的数值？

2 个答案: