Example:
If the elements of matrix are:
1 0 0
4 5 0
7 8 9
Sum of lower triangular matrix = 19
Required knowledge:
Basic C programming, For loop, Array, MatrixLower triangular matrix
Lower triangular matrix is a special square matrix whole all elements above the main diagonal is zero.Algorithm to find sum of lower triangular matrix:
Lower triangular matrix elements is shown in the below image. We need to find sum of all elements in the red triangular area.For any matrix A sum of lower triangular matrix elements can be defined as:
sum = sum + Aij (Where j < i).
Program:
/** * C program to find sum of lower triangular matrix */ #include <stdio.h> int main() { int A[3][3]; int row, col, sum = 0; /* * Reads elements in matrix from user */ printf("Enter elements in matrix of size 3x3: \n"); for(row=0; row<3; row++) { for(col=0; col<3; col++) { scanf("%d", &A[row][col]); } } /* * Finds sum of lower triangular matrix */ for(row=0; row<3; row++) { for(col=0; col<3; col++) { if(col<row) { sum += A[row][col]; } } } printf("Sum of lower triangular matrix = %d", sum); return 0; }
Output
Enter elements in matrix of size 3x3:
1 0 0
4 5 0
7 8 9
Sum of lower triangular matrix = 19
1 0 0
4 5 0
7 8 9
Sum of lower triangular matrix = 19
Happy coding ;)
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