Patterns

Key points

  1. Count the number of lines and loops for the same
  2. Find relation between line number, number of characters and spaces in that line. Apply loop for the same.
1
12
123
1234
12345
Code 
for (l = 1, l <= 5, l++){
    for (ch = 1, ch <= l, ch++){
        printf("%d", ch);
    }
    printf("\n");
}

1
23
456
78910
Code 
int x = 1;
for (l = 1; l <= 4; l++){
    for (ch = 1, ch <= l, ch++){
        printf("%d", ch);
        x++;
    }
    printf("\n");
}

1
11
111
1111
111
11
1
Code 
for (l = 1; l <= 7; l++)
{
    if (l <= 4){
        for (ch = 1; ch <= l; ch++)
        printf("1");
    }else{
        for (ch = 7; ch >= l; ch--)
        printf("1");
    }
    printf("\n");
}

1111
 111
  11
   1
  11
 111
1111
Code 
for (l = 1; l <=7; l++)
{
    if (l<=4){
        for (s = 2; s <= l; s++){
            printf(" ");
        }
        for (ch = 4; ch >= l; ch--){
            printf("1");
        }
    } else {
        for (s = 6; s >= l; s--){
            printf(" ");
        }
        for (ch = 4; ch <= l; ch++){
            printf("1");
        }
    }
}

1     1
11   11
111 111
1111111
Code 
int ch, l, s, s1 = 1, l1= 1;

    for (l = 1; l<= 4; l++)
    {
        for (ch = 1; ch <= l; ch++){
            printf("1");
        }
        for (s = 5; s >= s1; s--){
            printf(" ");
        }
        s1 += 2;
        for (ch = 1; ch <= l1; ch++){
            printf("1");
        }
        if (l != 3){
            l1++;
        }
        printf("\n");
    }

or

#include <stdio.h>

int main() {
    int rows = 4;
    int spaces = rows * 2 - 2;

    for (int i = 1; i <= rows; i++) {
        for (int j = 1; j <= i; j++) {
            printf("1");
        }
        for (int k = 1; k <= spaces; k++) {
            printf(" ");
        }
        spaces -= 2;
        for (int l = 1; l <= i; l++) {
            printf("1");
        }
        printf("\n");
    }
    return 0;
}

abcdefgfedcba
abcdef fedcba
abcde   edcba
abcd     dcba
abc       cba
ab         ba
a           a
Code 
  
#include <stdio.h>

int main(){
    int l, s, s1 = -2 ;
    char ch, ch1, end = 'g';

    for (l = 1; l <= end; ch++){
        for(ch = 'a'; l <= end; ch++;){
            printf("%c", ch);
        }
        for(s = 0; s <= s1; s++){
            printf(" ");
            s1 += 2;
        }
        
        if(l == 1){
            end--;
        }
        for(ch1 = ch-1; ch1 >= 'a'; ch1--;){
            printf("%c", ch1);

        }
        printf("\n");
    }
}