六个组数,第一组有3个数值，第二组有5个数值,第三组有7个数值,第四组有9个数值,第五组有11个数值,第六组有13个数值，分别输入每组的的每个数值，并求出每组数的平均值，请用C语言解决这个问题。

Sure! Here's a C code snippet to solve your problem:

#include <stdio.h>

int main() {
    int numGroups = 6;
    int groupSizes[] = {3, 5, 7, 9, 11, 13};
    int i, j;
    float sum, average;

    int groups[numGroups][groupSizes[numGroups-1]]; // Define a 2D array to store the input numbers
    
    // Input the numbers
    for (i = 0; i < numGroups; i++) {
        printf("Enter %d numbers for group %d:\n", groupSizes[i], i+1);
        for (j = 0; j < groupSizes[i]; j++) {
            scanf("%d", &groups[i][j]);
        }
    }

    // Calculate and display the average for each group
    for (i = 0; i < numGroups; i++) {
        sum = 0;
        for (j = 0; j < groupSizes[i]; j++) {
            sum += groups[i][j];
        }
        average = sum / groupSizes[i];
        printf("Average for group %d: %.2f\n", i+1, average);
    }

    return 0;
}

You can compile and run this code in a C compiler and input the numbers for each group. It will calculate and display the average for each group.