Question

I with the below code:

#include <stdio.h>

int main() {
    int numOfClasses;

    do{
    printf("How many classes do you have?\t");
    scanf("%d", &numOfClasses);
    }while(numOfClasses < 1);

    int count = numOfClasses;
    char nameOfClass[30];
    int numOfGrades[30];
    printf("Which classes do you have, how many grades in each class?\n");
    for(int i = 0; i < count; i++){
            scanf("%s %d", &nameOfClass[i], &numOfGrades[i]);
    }
    for(int i = 0; i < count; i++){
            printf("%s : %d\n", nameOfClass[i], numOfGrades[i]);
    }

    return 0;
}

I want this program to to ask the user to input a class and the number of grades in that class. Later I will try to input each individual grade in that class, but for now I want to solve this.

When I run this I get this error message:

warning: format ‘%s’ expects argument of type ‘char *’, but argument 2 has type ‘int’ [-Wformat=]
printf("%s : %d\n", nameOfClass[i], numOfGrades[i]);
       ^

Answer 1

The variable char nameOfClass[30] should be two dimensional array as char nameOfClass[30][30]. As you are reading the name of classes. So, I changed it to two dimensional array. And you are reading string array using the statement: scanf("%s %d", &nameOfClass[i], &numOfGrades[i]); If you do not use two dimensional array then, your nameOfClass variable will point only last class name which is incorrect.

    int count = numOfClasses;
    char nameOfClass[30][30];
    int numOfGrades[30];
    printf("Which classes do you have, how many grades in each class?\n");
    for(int i = 0; i < count; i++){
            scanf("%s %d", nameOfClass[i], &numOfGrades[i]);
    }
    for(int i = 0; i < count; i++){
            printf("%s : %d\n", nameOfClass[i], numOfGrades[i]);
    }

Correct format specifier to print a string

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