1. Lecture 15: Projects Using Similar Data

2. What is an Array? An array is a data structure consisting of related data items of the same type. Stored in a group of memory locations Defining arrays int arrayName[ 100 ]; Examples int a[5]; float b[120], x[24]; … … a[0] 5 memory 10 15 3 23 a[1] a[2] a[3] a[4] Specifying the type of each element Name of the array The number of the elements

3. Passing Arrays to Functions The name of an array evaluates to the address of the first element of the array. Passing arrays To pass an array argument to a function, specify the name of the array without any brackets int anArray[100]; aFunction( anArray, 100 );  Array size usually passed to function Function knows where the array is stored Modifies original memory locations

4. Defining Function with Array Parameters The function’s parameter list must specify that an array will be received. void aFunction( int ary[ ], int size ) { …….. } Function prototype void aFunction( int ary[ ], int size ); Parameter names optional in prototype int ary[ ] could be written int [] int size could be simply int The header of the function The size of the array is NOT required. void aFunction( int [ ], int );

5. Defining Function with Array Parameters Using the type qualifier const. void aFunction( const int ary[ ], int size ) The modification of the array elements are NOT allowed. Any attempt to modify an element of the array in the function body results in a compile-time error. The header of the function

6. Passing Array Elements Passed by call-by-value. Array elements are like normal variables Pass subscripted name to function void modifyArrayElement( int arrayElement ); int array[ 10 ] = {0}; modifyArrayElement( array[1] ); modifyArrayElement( array[8] );

7. Practice Question Q. Which is the right way to pass an integer array argument ary to the following function? void func( int a[] ); int ary[25]; A. func( ary[25] ); B. func( ary[] ); C. func( ary ); D. func( ary[0] ); Solution: C

8. Practice Question Q. Which is NOT the right way to pass an integer array argument ary to the following function? #include #define SIZE 5; void func( int a[], int x ); int main( void ) { int b[SIZE] = {1, 2, 3, 4, 5}; func(b, b[1]); printf(“%d %d\n”, b[0], b[1]); return 0; } void func( int a[], int x) { int k; for (k = 0; k < SIZE; k++) a[k] *= 2; x *= 2; } A. 1 2 B. 2 4 C. 2 8 D. 1 4 Solution: B