Getting multiple float input using scanf but the input is allocated only to 1st variable-CodePudding

main() {
    float n1, n2, n3, n4, n5, agg_mrk, prcnt;
    printf("Enter the marks of five students ");
    scanf("%f, %f, %f, %f, %f", &n1, &n2, &n3, &n4, &n5);
    printf("the five number entered by u is %f, %f, %f,%f, %f", n1, n2, n3, n4, n5);
    agg_mrk = n1   n2   n3   n4   n5;
    prcnt = agg_mrk / 5;
    printf("The aggregate marks is %lf and the percentage is %f", agg_mrk, prcnt);
}

The first number is getting right value but all other numbers (n2, n3, n4, n5) showing garbage value:

CodePudding user response：

The input 67 78 90 56 78 does not match the expected syntax:

scanf("%f, %f, %f, %f, %f", &n1, &n2, &n3, &n4, &n5);

scanf() skips any leading white space, then expects a float value, then expects a ,, then ignores whitespace, then expects another float value, etc.

The input 67 78 90 56 78 does not have a comma after the first number so scanf() stops converting and returns 1, the number of successful conversions.

The values of n2, n3, n4 and n5 are unchanged, hence stay uninitialized, appearing as random values.

Note also that main must be defined with a return type of int.

Here is a modified version:

#include <stdio.h>

int main() {
    float n1, n2, n3, n4, n5, agg_mrk, prcnt;
    printf("Enter the marks of five students: ");
    if (scanf("%f %f %f %f %f", &n1, &n2, &n3, &n4, &n5) != 5) {
        printf("invalid input\n");
    } else {
        printf("the five number entered by u is %f, %f, %f,%f, %f\n",
               n1, n2, n3, n4, n5);
        agg_mrk = n1   n2   n3   n4   n5;
        prcnt = agg_mrk / 5;
        printf("The aggregate marks is %f and the percentage is %f\n",
               agg_mrk, prcnt);
    }
    return 0;
}

CodePudding user response：

Try using this instead in 4th line:

scanf("%f %f %f %f %f", &n1, &n2, &n3, &n4, &n5);

So you can clearly see, when you put "," after %input, it expects a variable or a memory to store it into. Don't confuse scanf with printf, below code will work correctly with commas too.

printf("%f, %f, %f, %f, %f", n1, n2, n3, n4, n5);

I hope that you are able to spot the difference now.